I'm printing TPU from Creality and found the following: even with a perfectly calibrated extruder, the extrusion factor must be adjusted waaaay down, at the moment it is on 0.75! This is with a direct drive and a 0.6mm nozzle.
I started at 1.00, but I kept getting blobs that got stuck to the nozzle while it was moving, specially at the start and end of moves and where the layer change happens. Those blobs were then the reason the print starts flexing away from the nozzle when it passes and then it deposits the tpu next to the perimeter,in thin air...
Then by adjusting the flow-rate down to 80 and 75% on the control box I get much better results, no blobs and spilling.
Retraction is 4mm
Another thing is cooling: at first I used 40% but it is now up to 100% ( 2 fans on either side)and this helps against curling of any end of a perimeter and where the nozzle returns.